#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

const int N = 310;

typedef long long ll;

int n;
ll x[N], y[N];

int main() {
    cin >> n;

    for (int i = 1; i <= n; i++)
        cin >> x[i] >> y[i];

    int cnt = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n; j++) {
            for (int k = j + 1; k <= n; k++) {
                if (x[i] == x[j] && x[j] == x[k])
                    continue;

                if (y[i] == y[j] && y[j] == y[k])
                    continue;

                if ((y[j] - y[i]) * (x[k] - x[j]) != (x[j] - x[i]) * (y[k] - y[j]))
                    cnt++;
            }
        }
    }

    cout << cnt << endl;
    return 0;
}